This invention relates to a punch retainer for use on stamping presses and, more particularly, to a punch retainer generally of the type disclosed in my U.S. Pat. No. 4,174,648, dated Nov. 20, 1979. In my aforesaid patent there is disclosed a punch retainer provided with a latch having cylindrically shaped opposite sides which are adapted to tangentially engage in wedging relationship an inclined face on the punch and an inclined face of a socket within the punch retainer. The latch is urged into said tangential wedging engagement with the punch and the inclined wall of the socket by means of a spring. While the arrangement shown in said patent is admirably suited for use with punches having a circular punching end, experience has shown that where the punch is provided with a non-circular punching end the dimensional tolerances of the cooperating surfaces on the punch, the latch and the retainer are critical and must be closely controlled if the punched hole has to be within very close tolerances. Unless such tolerances are closely controlled, the punch might be firmly seated within the socket but the punching end thereof may be rotated at least slightly from its desired accurately oriented position.
The primary object of the present invention is to provide a simple mechanism for firmly retaining a punch within a retainer so that the non-circular punching end of the punch is accurately oriented in a circumferential sense relative to the retainer.
A more specific object of the invention resides in the provision of a spring housed within the retainer for engaging a flat surface on the punch which is accurately machined relative to the non-circular punching end of the punch.